My 2001 xtreme blazer has a slight miss at idle and while driving just done tune up. OBD code read a fuel tank pressure sensor how hard is that to change.

 

It is not difficult at all to change. I didn't even need to drop the tank on my blazer to do it.
On my 01 blazer LT dropping the spare tire allowed for easy access to the sensor. It is located right next to the fuel pump.